Aqueous extracts of anoectochilus spp. kinsenoside-comprising pharmaceutical compositions useful for hepatoprotection and uses of the same

ABSTRACT

A pharmaceutical composition useful for hepatoprotection is provided. The composition comprises an effective amount of kinsenoside or a pharmaceutically acceptable salt or ester thereof. An aqueous extract of  Anoectochilus  spp. is also provided. The extract is substantially free of ethyl acetate-philic components.

FIELD OF THE INVENTION

The present invention relates to a pharmaceutical composition comprising kinsenoside, which is useful in hepatoprotection. This invention also relates to an aqueous extract of Anoectochilus spp.

BACKGROUND OF THE INVENTION

Anoectochilus spp. belong to Orchidaceae, wherein Anoectochilus formosanus Hayata is regarded as “the king of medicines” by the Taiwanese because of its diverse pharmacological effects, such as reducing blood pressure and blood sugar levels, hepatoprotection, and enhancing immunity. Therefore, Anoectochilus formosanus Hayata has generally been used as a folk medicine for treating liver fibrosis, diabetes and cardiovascular diseases.

The crude extracts of Anoectochilus formosanus Hayata have several pharmacological effects, such as antiosteoporosis (Shih C C et al., J Ethnopharmacol, 2001, 77: 233-228), antihyperglycemic effect (Shih C C et al., Clin Exp Pharmacol Physiol, 2002, 29: 684-688.; JP7076522), lipid-lowering effect (JP 6293655), improving memory and learning (Cheng H Y et al., J Chin Med, 2003, 14: 235-245.), inhibiting the oxidation of LDL (Shih C C et al., Am J Chin Med, 2003, 31: 25-36.), and treating tumors (U.S. Pat. No. 7,033,617). In addition, Lin et al. showed that Anoectochilus formosanus Hayata has hepatoprotective effects on carbon tetrachloride (CCl₄)- or acetaminophen-induced acute hepatitis (Lin J M et al., Am J Chin Med, 1993, 11: 59-69; Lin C C et al., Am J Chin Med, 2000, 28: 87-96). Du et al. also showed that aqueous extracts of Anoectochilus formosanus Hayata inhibited cell damage induced by CCl₄ in primary cultured rat hepatocytes (Du X M et al., Phytother Res, 2003, 17: 30-33). Recently, it was also shown that an aqueous extract of Anoectochilus formosanus Hayata attenuated hepatic fibrosis induced by both CCl₄ and dimethyinitrosamine in rats (Shih C C et al., Clin Exp Pharmacol Physiol, 2004, 31: 620-625; Shih C C et al., Phytomedicine, 2005, 12: 453-460).

Thus, the research has shown that Anoectochilus formosanus Hayata has an hepatoprotective effect. Since this herb is highly regarded in the Taiwanese herb market and cannot be colonal propagated quickly enough to sustain its uses, its prevalence in nature has depleted substantially. Although the vegetative propagation of Anoectochilus formosanus Hayata using tissue culture and modified cultivation of Anoectochilus spp. root have been achieved (Shiau Y J et al., Bot Bull Acad Sin, 2002, 43: 123-130; JP10056875(A)), only limited amounts of Anoectochilus spp. can be produced. Therefore, if the hepatoprotective compound(s) in Anoectochilus formosanus is(are) identified, the hepatoprotective preparations containing the compound(s) will be provided via synthesized and large-scale production.

The purpose of the present invention is to identify the major active compounds from Anoectochilus formosanus Hayata from both in vivo and in vitro experiments. Additionally, a fraction from Anoectochilus formosanus Hayata adverse to liver is also identified.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a pharmaceutical composition useful for hepatoprotection, which comprises an effective amount of a compound of formula (I):

or a pharmaceutically acceptable salt or ester thereof, wherein the compound of formula (I) is kinsenoside.

In another aspect, the present invention provides extracts of Anoectochilus spp. that are substantially free of ethyl acetate-philic components.

In further aspect, the present invention provides uses of the compound of formula (I) or a pharmaceutically acceptable salt or ester thereof or the said extracts of Anoectochilus spp. for the manufacture of a pharmaceutical preparation for hepatoprotection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the chromatographic profiles of Fraction 4 by using preparative high performance liquid chromatography (HPLC). The fraction AFEW-2 was purified further on a silica gel with chloroform/ethanol as the mobile phase to give four fractions (Fraction 1, Fraction 2, Fraction 3, and Fraction 4).

FIG. 2 shows a graph of mass spectroscopy of the major components of Fraction 4 in AFEW-2.

DESCRIPTION OF THE INVENTION

The following describes the techniques and preferred embodiments in detail to enable those having ordinary skill in the art to realize the characteristics of the invention.

The term “ethyl acetate-philic components” as used herein refers to the components soluble in water and can be removed by partitioning with ethyl acetate.

The term “AFE” as used herein refers to the aqueous extracts of Anoectochilus formosanus Hayata.

The term “AFEW” as used herein refers to the water-soluble portion of the aqueous extract of Anoectochilus formosanus Hayata from which the ethyl acetate-soluble portion is removed, i.e. the water-soluble portion substantially free of ethyl acetate-philic components.

The term “AFEE” as used herein refers to an ethyl acetate-philic fraction of the extracts of Anoectochilus formosanus Hayata, i.e. an ethyl acetate portion obtained from partitioning the crude aqueous extracts of Anoectochilus formosanus Hayata with ethyl acetate.

The terms “fraction AFEW-1”, “fraction AFEW-2”, “fraction AFEW-3”, “fraction AFEW-4”, and “fraction AFEW-5” as used herein refer to five fractions obtained from an AFEW subjected to a Diaion HP-20 column and respectively eluted with H₂O, 10% methanol in water, 20% methanol in water, 50% methanol in water, and 100% methanol.

This invention relates to both a pharmaceutical composition comprising a kinsenoside useful for hepatoprotection and an extract of Anoectochilus spp. that is substantially free of ethyl acetate-philic components. The invention also relates to uses of the pharmaceutical composition and the extract in the manufacturing of a pharmaceutical preparation.

It is known that the compound kinsenoside has a structure of formula (I):

The inventors of the present invention found that the compound of formula (I) identified in Anoectochilus formosanus Hayata is one major component with a hepatoprotective effect. Specifically, those skilled in the art know that CCl₄ may cause hepatocellular damage and induce hepatitis in mice; however, the inventors of the present invention found that different extract fractions of Anoectochilus formosanus Hayata can reduce hepatocellular damage of CCl₄-induced hepatitis in mice, especially in the fractions with a large amount of the compound of formula (I). On the other hand, the ethyl acetate-philic fraction of the extract of Anoectochilus formosanus Hayata enhances hepatocellular damage. Without being bound by theory, it is believed that the compound of formula (I) is a major component in rendering the Anoectochilus formosanus Hayata hepatoprotective effect.

One aspect of this invention therefore provides a pharmaceutical composition useful for hepatoprotection, which comprises an effective amount of compound of formula (I) or a pharmaceutically acceptable salt or ester thereof. Administration of the pharmaceutical composition can be carried out in the appropriate ways, including, but not limited to, oral, subcutaneous, and/or intravenous administration. The compound of formula (I) or a pharmaceutically acceptable salt or ester thereof may be administered either alone or in combination with one or more pharmaceutically acceptable adjuvants. Furthermore, the compound of formula (I) or a pharmaceutically acceptable salt or ester thereof can be used in veterinary and human medicine.

Accordingly, the pharmaceutical composition of this invention may be formulated into any appropriate form used in hapatoprotection. For the preparation of the pharmaceutical preparation used in oral administration, the compound of formula (I) or a pharmaceutically acceptable salt or ester thereof can be mixed with suitable additives, such as excipients, stabilizers, or inert diluents. The suitable forms for administration such as tablets, coated tablets, capsules, softcapsules, microcapsules, or aqueous solution, are prepared using the conventional methods. Suitable excipients that are inert to the activity of the compound of formula (I), include, for example, gum Arabic, lactose, dextrose, or starch, especially corn starch. Additionally, tablets also can be prepared by dry or wet granulation. Examples of suitable oily excipients or solvents are vegetable and animal oils, including, but not limited to, olive oil, sunflower oil, or fish liver oil.

For the preparation of the pharmaceutical preparation used in subcutaneous or intravenous administrations, the compound of formula (I) or a pharmaceutically acceptable salt or ester thereof can be prepared into the solutions, suspensions, or emulsions and be optionally mixed with suitable additives (such as solubilizers, emulsifiers, or other adjuvants). Examples of suitable solvents include water, physiologic saline solution, alcohols (such as ethanol, propanol, or glycerol), sugar solutions (such as dextrose or mannose solution), or a combination thereof.

The pharmaceutical composition of this invention optionally contains appropriate amounts of other pharmaceutically acceptable adjuvant(s) such as surfactants, emulsifiers, solubilizers, and the like.

It should be noted that the desired hepatoprotective effect of the pharmaceutical composition according to this invention is caused by the presence of the compound of formula (I) or a pharmaceutically acceptable salt or ester thereof. The amounts thereof are not critical. The frequency of administrating the pharmaceutical composition of this invention, for example, once daily, multiple times daily, or once every few days, depends on the conditions of the subject. Generally, the pharmaceutical composition of this invention contains, as the compound of formula (I), from about 0.1 to about 10% by weight of the compound of formula (I) or a pharmaceutically acceptable salt or ester thereof, especially from about 1 to about 5% by weight.

The amount of the compound of formula (I) or a pharmaceutically acceptable salt or ester thereof provided to a patient will vary depending on the severity of the disease to be treated. Generally, the amount of said compound of formula (I) provided to the patient is about 20 mg to about 200 mg per day for an adult who weighs 60 kg, more preferably about 40 mg to about 180 mg and most preferably about 120 mg to about 150 mg. However, the amount may be several-fold or more than 10-fold increased when treating patients with acute conditions, such as acute hepatitis.

The compound of formula (I) provided in the pharmaceutical composition of this invention can be prepared from a natural source or synthetic procedure. Preferably, the compound of formula (I) is prepared from Anoectochilus spp., especially Anoectochilus formosanus Hayata. Therefore, the compound of formula (I) can be prepared from Anoectochilus spp. using any appropriate extraction and isolation methods. See, Ito A et al., Phytochemistry, 1993, 33: 1133-1137; Du X M et al., Phytochemistry, 1998, 49: 1925-1928, each of which is incorporated herein by reference in its entirety. Further, the compound with formula (I) also can be prepared by total synthesis (See Zhang X et al., Chinese Journal of Synthetic Chemistry, 2004, 12, 317-318, which is incorporated herein by reference in its entirety).

The pharmaceutical composition of this invention may further be optionally combined with other active ingredients such as a hepatoprotective agent, hepatorepair agent or prophylactic agent for hepatodamage, wherein the active ingredients do not interfere with the activity of the compound of formula (I).

The present invention also relates to the extracts of Anoectochilus spp. that are substantially free of ethyl acetate-philic components. As described above, the ethyl acetate-philic fraction of the extracts of Anoectochilus spp. enhances hepatocellular damage. It is believed that an aqueous extract of Anoectochilus spp. substantially free of ethyl acetate-philic components can effectively prevent potential damages caused by the treatment of extracts of Anoectochilus spp. in subjects.

Preferably, the extract of Anoectochilus spp. according to the present invention is an aqueous extract of Anoectochilus spp. substantially free of ethyl acetate-philic components. The aqueous extract of Anoectochilus spp. can be prepared as follows: (1) fresh whole plants of Anoectochilus spp. are extracted with water, (2) the filtrate is partitioned with ethyl acetate, and (3) the ethyl acetate-philic fraction is removed. If necessary, the filtrate is partitioned successively with ethyl acetate to possibly reduce the ethyl acetate-soluble components.

Advantageously, the extracts of Anoectochilus spp. according to the present invention are substantially free of ethyl acetate-soluble components that are adverse to liver function; the said extracts of Anoectochilus spp. are used as an antiosteoporosis agent, hypoglycemic agent, or hypolipidemic agent, and applied in the treatment of tumor, improving memory and learning, or inhibiting the oxidation of the low density lipoprotein, for instance. Accordingly, the extracts of Anoectochilus spp. preferably comprise the compound of formula (I) when they are used in the hepatoprotection.

Furthermore, the present invention relates to the use of said aqueous extracts of Anoectochilus spp. for the manufacturing of a pharmaceutical preparation for the treatment of osteoporosis, hyperglycemia, hyperlipidemia, and tumors, as well as the improvement of memory and learning, inhibiting the oxidation of low density lipoprotein, and hepatoprotection.

The following examples are offered to further illustrate this invention.

Materials and Methods (A) Plant Material

Anoectochilus formosanus Hayata plants were purchased from Yu-Jung Farm (Pu-Li, Taiwan) where they are cultivated. The plants were identified by the Institute of Chinese Pharmaceutical Sciences, China Medical University, where a plant specimen has been deposited with accession number CMU AF 0609.

(B) Reagents

-   (1) Hydroxyproline, p-dimethylaminobenzoaldehyde,     polyvinylpyrrolidone and hydrogen peroxide were provided by Sigma     Chemical Co. (St Louis, Mo., USA). -   (2) Carbon tetrachloride was obtained from Shimakyu Pure Chemicals     (Osaka, Japan). -   (3) DMEM (Dulbecco's modified Eagle's medium) was purchased from     Hyclone (Logan, Utah, USA). -   (4) Penicillin, streptomycin, amphotericin B and fetal bovine serum     were purchased from Gibco Laboratories (Grand Island, N.Y., USA).

(C) Extraction and Isolation

-   (1) Fresh whole plants of Anoectochilus formosanus Hayata (10 kg)     were extracted with water (100 L) and then filtrated to yield an     aqueous extract of Anoectochilus formosanus Hayata (AFE). The AFE     was then partitioned successively with ethyl acetate (25 mL×3). The     ethyl acetate layers were combined to obtain an ethyl acetate     fraction (AFEE). The water-soluble layers were combined to obtain a     water-soluble portion (AFEW). Alternatively, AFE can be prepared by     heating dried plants of Anoectochilus formosanus Hayata in water. -   (2) Both the ethyl acetate fraction (AFEE) and water-soluble portion     (AFEW) were evaporated under a reduced pressure, yielding 47.4 g of     a greenish oily residue and 218.4 g of a red residue, respectively.     A red residue of AFEW (210 g) was subjected to a Diaion HP-20 column     (Nippon Ressui Co., Japan) and eluted with H₂O, 10%, methanol in     water, 20% methanol in water, 50% methanol in water, and 100%     methanol to give five fractions (AFEW-1, AFEW-2, AFEW-3, AFEW-4, and     AFEW-5). The dry weights of fractions AFEW-1 to AFEW-5 were 141.38     g, 22.06 g, 8.16 g, 9.21 g and 3.78 g, respectively.

A general outline of the above preparation is provided in Scheme I,

-   (3) The AFEW-2 fraction (10 g) was purified further on a silica gel     (Si 60 F245; Merck, Germany) with chloroform/ethanol (8:3˜15:8     concentration gradient) as the mobile phase to give four fractions     (Fraction 1 to Fraction 4). Fraction 4 (4.5 g) was applied to the     preparative high performance liquid chromatography (HPLC) to yield a     pure compound (4.1 g). The pure compound was identified as     kinsenoside, i.e. the compound of formula (I).

The conditions used for preparative HPLC were as follows: pump: Shimadzu LC-8A (Kyoto, Japan); mobile phase: water; column: Mightysil ODS RP-18 Aqua column (i.d. 20 mm, 250 mm long; 5 μm particle size; Kanto Chemical Co., Tokyo, Japan).

The chromatographic profile of Fraction 4 is shown in FIG. 1, wherein the Fraction 4 comprises 77.6% of major compound. The pure compound was identified by mass spectroscopy (Jeol GCmate, Tokyo, Japan) as shown in FIG. 2. Extensive NMR analysis (¹H, ¹³C, DEPT, COSY, HMQC, HMBC; Jeol 400 MHz, Tokyo, Japan) identified the major compound as kinsenoside: 3-(R)-3-β-D-glucopyranosyloxybutanolide, i.e. compound of formula (I).

Table 1 gives the complete NMR assignments of kinsenoside.

TABLE 1 ¹³C and ¹H NMR spectral data of kinsenoside (400 MHz, DMSO-d_(δ)) C H 1 175.8 2 2.87 (dd, 17.8. 6.3) 2 34.9 — 2.48 (dd, 17.9. 1.3) 3 74.3 3 4.59 (dddd 6.0, 3.6, 2.2, 1.4) 4 74.0 4 4.41 (dd, 10.2. 5.1) 4.38 (dd, 10.3. 1.8) G-1 102.1 G-1 4.24 (d, 7.8) G-2 73.1 G-2 2.92 (m) G-3 76.9 G-3 3.94 (m) G-4 69.9 G-4 3.04 (m) G-5 76.5 G-5 3.13 (m) G-6 61.0 G-6 3.44 (m) 3.66 (dd, 11.7. 5.8) OH2 OH2  4.9 (d, 4.8) OH3 OH3  5.0 (d, 5.1) OH4 OH4  4.8 (d, 5.4) OH6 OH6  4.5 (t, 5.8)

(D) Determination of Kinsenoside Content

The kinsenoside contents in both the AFEW and AFEW-1 to AFEW-5 were determined by HPLC. The results indicated that the kinsenoside contents in AFEW, AFEW-2 and AFEW-3 fractions were approximately 18%, 82% and 35%, respectively. No kinsenoside was detected in fraction AFEW-1. Kinsenoside could be detected in fractions AFEW-4 and AFEW-5, but the content was very low.

Conditions used for HPLC were as follows: pump: Shimadzu LC-10ATvp; refractive index detector: Shimadzu RID-10A; column: Mightysil ODS RP-18 GP Aqua column (i.d. 4.6 mm, 250 mm long; 5 μm particle size); guard column: Mightysilk 4.6 mm×6 mm. The solvent system used was Milli-Q water at a flow rate of 0.5 mL/min.

EXAMPLE 1 CCl₄-induced Chronic Hepatitis in Mice

Male ICR mice were purchased from the National Laboratory Animal Center (Taipei, Taiwan) and were used for experiments when they reached 24 to 26 g body weight. Chronic hepatitis was induced in mice by oral administration of 0.1 mL of CCl₄ (diluted 1:19 in olive oil) per 10 g body weight twice a week for 3, 8 or 9 weeks. On the days of the CCl₄ treatment, the time interval between CCl₄ and drug administrations was 5 hours to avoid absorption interference. After the blood was drawn at the end of the experimental period, all mice were sacrificed at the same time and the liver and spleen were quickly removed and weighed after washing with cold normal saline and blotting dry. The largest lobe of liver was weighed and then completely dried at 100° C. for determination of the hydroxyproline content according to the method designed by Neuman and Logan (Neuman R E and Logan M A, J Biol Chem, 1950, 184: 299-306). Dried liver tissue (approx. 60 mg) was hydrolysed, then oxidized by H₂O₂ and reacted with p-dimethylaminobenzoaldehyde. The absorbance of the colored product was determined at 540 nm. The amount of hydroxyproline was expressed in μg/g wet tissue. The levels of plasma glutamate-pyruvate transaminase (GPT) and albumin were assayed spectrophotometrically (Cobas Mira Plus Chemistry Analyzer, Switzerland) using clinical test kits (Roche Diagostics, Mannheim, Germany).

Experiment I

Chronic hepatitis was induced in mice by CCl₄ administration for 3 weeks. Since AFEE did not dissolve in water, it was suspended in polyvinylpyrrolidone (PVP). Therefore, the experiments were divided into two parts. For part I, mice were divided into three groups, those that received CCl₄ with H₂O, CCl₄ with AFE (2000 mg/kg) or CCl₄ with AFEW (1500 mg/kg) p.o. daily for 3 weeks. The control group received olive oil (vehicle for CCl₄) with H₂O. In part II, the mice were divided into two groups, those that received CCl₄ with PVP or CCl₄ with AFEE (500 mg/kg) p.o. daily for 3 weeks. The control group received the olive oil vehicle with PVP. After 1 week of CCl₄ treatment, blood was collected via the retro-orbital sinus of mice for serum GPT assays.

The results are shown in Table 2. CCl₄ treatment caused hepatocellular damage in mice, as indicated by an increase in plasma GPT activity after 1 and 3 weeks of CCl₄ administration. Mice that were treated daily with AFE (2000 mg/kg) or AFEW (1500 mg/kg) showed protection against CCl₄-induced hepatitis, with a reduced GPT level. In contrast, AFEE (500 mg/kg, daily) enhanced the increase in plasma GPT levels caused by CCl₄ administration for 1 and 3 weeks. These results clearly show that AFEW has a hepatoprotective action, while AFEE is adverse to liver function.

TABLE 2 Effects of AFE, AFEE and AFEW on the activities of serum GPT in CCl₄-treated mice after 1 and 3 weeks GPT (U/L) Drugs  Dose (mg/kg) Week 1 Week 3 Olive oil + H₂O —  40.3 ± 3.5  37.9 ± 2.0 CCl₄ + H₂O — 299.3 ± 15.9^(a) 1266.5 ± 162.0^(a) CCl₄ + AFE 2000 160.5 ± 47.5^(c)  600.0 ± 142.7^(b) CCl₄ + AFEW 1500 195.5 ± 29.7^(c)  306.0 ± 22.6^(c) Olive oil + PVP —  39.1 ± 2.9  37.5 ± 1.8 CCl₄ + PVP 170.7 ± 17.4^(d)  740.0 ± 120.2^(d) CCl₄ + AFEE  500 492.6 ± 103.6^(e) 1398.0 ± 268.6^(e) All values are mean ± SE (n = 8). ^(a)p < 0.001 compared with olive oil + H₂O group. ^(b)p < 0.05, ^(c)p < 0.01 compared with CCl₄ + H₂O group. ^(d)p < 0.001 compared with olive oil + PVP group. ^(e)p < 0.05 compared with CCl₄ + PVP group.

Experiment II

Chronic hepatitis was induced in ICR mice by CCl₄ administration for 8 weeks. Since AFEW-4 did not dissolve in water, it was suspended in PVP. The experiment was divided into two parts. In part I, mice were divided into six groups, those that received CCl₄ with H₂O, CCl₄ with AFEW (1500 mg/kg), CCl₄ with AFEW-1 (1055 mg/kg), CCl₄ with AFEW-2 (130 mg/kg), CCl₄ with AFEW-3 (50 mg/kg) or CCl₄ with AFEW 5 (190 mg/kg) p.o. daily for 8 weeks. The control group received the olive oil vehicle with H₂O. In part II, mice were divided into two groups those that received CCl₄ with PVP or those that received CCl₄ with AFEW-4 (75 mg/kg) p.o. daily for 8 weeks. The control group received the olive oil vehicle with PVP.

An animal model of chronic hepatitis induced in mice by oral administration of CCl₄ twice a week for 8 weeks was used to investigate the hepatoprotective effect of AFEW-1 to AFEW-5. The result is shown in Table 4. Compared to the control group in week 8, the CCl₄-treated group had a markedly increased GPT activity, spleen weight and liver hydroxyproline level, and a decreased plasma albumin level. AFEW and AFEW-2 (a subfraction of AFEW) both reduced plasma GPT activity, spleen weight and liver hydroxyproline level in mice, and diminished the hypoalbuminemia. AFEW-1 reduced plasma GPT activity and liver hydroxyproline level in mice. AFEW-5 only reduced plasma GPT level in mice. According to these results, the subfraction of AFEW in which AFEW-2 was the most hepatoprotective fraction, while AFEW-1 only showed partial hepatoprotective action. AFEW-5 showed effects on the plasma GPT activity; however, there was no effect on improving liver fibrosis (hydroxyproline content is an indicator of liver fibrosis).

TABLE 4 Effect of AFEW and AFEW-1 to AFEW-5 on the levels of plasma GPT and albumin, spleen weight and contents of hepatic hydroxyproline in CCl₄-treated mice after 8 weeks Plasma Liver Dose Plasma GPT albumin Spleen weight hydroxyproline Drugs (mg/kg/day) (U/L) (g/dL) (g) (μg/g tissue) Olive oil + H₂O —  36.4 ± 4.0 3.5 ± 0.1 0.18 ± 0.01  504.0 ± 26.6 CCl₄ + H₂O — 436.9 ± 62.5^(b) 2.9 ± 0.1^(b) 0.21 ± 0.03^(a) 1062.0 ± 189.5^(b) CCl₄ + AFEW 1500 343.0 ± 19.0^(c) 3.4 ± 0.1^(d) 0.15 ± 0.01^(c)  698.0 ± 51.3^(c) CCl₄ + AFEW-1 1055 177.8 ± 20.0^(e) 3.1 ± 0.1 0.18 ± 0.01  660.1 ± 61.7^(c) CCl₄ + AFEW-2 130 246.9 ± 32.8^(d) 3.4 ± 0.0^(d) 0.15 ± 0.02^(c)  598.8 ± 39.1^(d) CCl₄ + AFEW-3 50 353.8 ± 20.4 3.2 ± 0.2 0.16 ± 0.01  845.2 ± 110.7 CCl₄ + AFEW-5 190 258.6 ± 23.8^(d) 3.3 ± 0.3 0.20 ± 0.02  858.5 ± 54.0 Olive oil + PVP —  38.3 ± 3.3 3.4 ± 0.2 0.18 ± 0.02  499.6 ± 27.6 CCl₄ + PVP — 388.7 ± 59.0^(e) 2.8 ± 0.1^(e) 0.22 ± 0.02^(e) 1029.0 ± 170.6^(e) CCl₄ + AFEW-4 75 603.3 ± 192.9 3.2 ± 0.1 0.17 ± 0.03  898.0 ± 98.6 All values are mean ± SE (n = 10). ^(a)p < 0.01, ^(b)p < 0.001 compared with olive oil + H₂O group. ^(c)p < 0.05, ^(d)p < 0.01 compared with CCl₄ + H₂O group. ^(e)p < 0.001 compared with olive oil + PVP group.

Experiment III

Male BALB/c mice were purchased from the National Laboratory Animal Center (Taipei, Taiwan) and were used for experiments when they reached approximately 22 g body weight. Chronic hepatitis was induced in mice by oral administration of 0.1 mL of CCl₄ (diluted 1:19 in olive oil) per 10 g body weight twice a week for 9 weeks. The experiment was divided into two parts. In part I, mice were divided into three groups, those that received CCl₄ with H₂O, CCl₄ with AFEW-1 (300 mg/kg), or CCl₄ with AFEW-1 (600 mg/kg) p.o. daily for 9 weeks. The control group received the olive oil vehicle with H₂O. In part II, the mice were divided into three groups, those that received CCl₄ with H₂O, CCl₄ with AFEW-2 (75 mg/kg), or CCl₄ with AFEW-2 (150 mg/kg) p.o. daily for 9 weeks. The control group received the olive oil vehicle with H₂O.

After 3 and 9 weeks of CCl₄ treatment, blood was collected via the retro-orbital sinus of the mice for serum GPT assays. The results are shown in Table 5. CCl₄ treatment caused hepatocellular damage in mice, as indicated by a marked increase in plasma GPT activity after 3 and 9 weeks of CCl₄ administration. According to these results, mice treated with AFEW-1 (600 mg/kg) and AFEW-2 (150 mg/kg) showed hepatoprotective action against chronic hepatitis induced by CCl₄, as the plasma GPT levels were significantly reduced in mice.

TABLE 5 Effect of AFEW-1 and AFEW-2 on the activities of serum GPT in CCl₄-treated BALB/c mice at 3 and 9 weeks GPT (U/L) Drugs Dose (mg/kg) Week 3 Week 9 Olive oil + H₂O —  35.9 ± 3.8  33.4 ± 10.7 CCl₄ + H₂O — 1471.7 ± 408.2^(a) 2578.3 ± 874.1^(a) CCl₄ + AFEW-1 300 1126.7 ± 310.8  209.7 ± 745.3 CCl₄ + AFEW-1 600  838.3 ± 220.4^(b) 1552.0 ± 707.3^(b) Olive oil + H₂O —  36.7 ± 1.1  35.6 ± 2.1 CCl₄ + H₂O — 1577.1 ± 114.0^(a) 1984.2 ± 224.9^(a) CCl₄ + AFEW-2  75 1329.1 ± 4480.0 1354.3 ± 669.8 CCl₄ + AFEW-2 150 1120.0 ± 185.1^(b) 1018.5 ± 354.0^(b) All values are mean ± SE(n = 10). ^(a)p < 0.001, ^(b)p < 0.05, ^(c)p < 0.01, ^(d)p < 0.001 compared with CCl₄ + H₂O group.

EXAMPLE 2 Cell Culture and Hydrogen Peroxide Cytotoxicity Assay

BALB/c normal liver (BNL) cells were purchased from Bioresources Collection and Research Center (Hsinchu, Taiwan). Cell lines were grown in DMEM (Dulbecco's modified Eagle's medium) with 50 IU/mL penicillin, 50 μg/mL streptomycin, 50 IU/mL amphotericin B and 10% fetal bovine serum. For cytotoxicity assays, cells (5×10³ cells/well) were plated into 96-well culture plates and allowed to attach overnight. The medium was replaced with fresh medium (as control) or with various concentrations of AFEW, AFEW-1 or kinsenoside for 16 hours. The cells were then washed with PBS and further treated with various doses of hydrogen peroxide (0.125-4.00 μM) for 2 hours. After H₂O₂ cytotoxic treatment, the percentage of viable cells was determined using a CellTiter 96 Aqueous Non-Radioactive Cell Proliferation Assay kit (Promega, Madison, Wis., USA). Reagent solution (20 μL) was added to each well and incubated at 37° C. in humidified 5% CO₂ for 1 hour. Then, the absorbance was measured at 490 nm using a 96-well plate reader (Multiskan Spectrum, Labsystem, Thermo Electron Corporation, Finland).

In vitro Experiment and Results

In the in vitro experiment, a pure kinsenoside was used to replace AFEW-2. The hepatoprotective effect of AFEW, AFEW-1 and kinsenoside on the injury induced by H₂O₂ in BNL was shown in Table 6. The LD₅₀ concentrations of H₂O₂ were markedly increased in BNL cells by pretreatment with AFEW (100 and 200 μg/mL) or kinsenoside (20 and 40 μg/mL), but not by AFEW-1 (75 and 150 μg/mL), indicating that the hepatoprotective effect of AFEW is mostly due to kinsenoside, the major compound of AFEW-2.

TABLE 6 Effect of pretreatment with AFEW, AFEW-1 and kinsenoside on the LD₅₀ of H₂O₂-induced BNL cell death H₂O₂ LD₅₀(μM) Drug Concentration (μg/mL) (95% confidence limits) Control — 0.69 (0.64-0.76) AFEW 100 0.81 (0.75-0.87)^(a) AFEW 200 1.05 (0.96-1.14)^(a) AFEW-1 75 0.62 (0.58-0.66) AFEW-1 150 0.62 (0.57-0.67) Kinsenoside 20 0.81 (0.74-0.88)^(a) Kinsenoside 40 1.17 (1.01-1.36)^(a) Data represent the means of triplicate determination from three experiments. ^(a)Significance of difference compared with control.

Statistical Analyses

Data from in vivo experiments were treated by one-way analysis of variance and Dunnett's test was applied. The significance level was set at p<0.05. The LD₅₀ values and 95% confidence limits for H₂O₂-induced BNL cell death were calculated according to the method of Litchfield and Wilcoxon (Litchfield J T, Wilcoxon F. 1949. A simplified method of evaluating dose-effect experiments. J Pharmacol Exp Ther 96: 99-113). The significance of differences between the LD₅₀ values was also tested using this method.

The above examples are offered to illustrate the principle and effects of the present invention, and are not intended to limit the invention in any manner. Indeed, various modifications of the invention in addition to those described herein will become apparent to those skilled in the art from the foregoing description and the accompanying figures without departing from the spirit of the invention. Such modifications are intended to fall within the scope of the appended claims. 

1. A pharmaceutical composition useful for hepatoprotection, which comprises an effective amount of a compound of formula (I)

or a pharmaceutically acceptable salt or ester thereof.
 2. The pharmaceutical composition according to claim 1, wherein the compound of formula (I) is obtained from Anoectochilus spp.
 3. The pharmaceutical composition according to claim 2, wherein the Anoectochilus spp. is Anoectochilus formosanus Hayata.
 4. The pharmaceutical composition according to claim 1, which contains (as the compound of formula (I)) from about 0.1 to about 10% by weight of the compound of formula (I) or a pharmaceutically acceptable salt or ester thereof.
 5. The pharmaceutical composition according to claim 4, which contains (as the compound of formula (I)) from about 1 to about 5% by weight of the compound of formula (I) or a pharmaceutically acceptable salt or ester thereof.
 6. An extract of Anoectochilus spp., which is substantially free of ethyl acetate-philic components.
 7. The extract of Anoectochilus spp. according to claim 6, which is an aqueous extract.
 8. The extract of Anoectochilus spp. according to claim 6, which comprises a compound of formula (I):


9. The extract of Anoectochilus spp. according to claim 8, which is used for hepatoprotection.
 10. A use of a compound of formula (I) or a pharmaceutically acceptable salt or ester thereof for the manufacture of a pharmaceutical preparation for hepatoprotection:


11. A use of the extract of Anoectochilus spp. according to claim 6 for the manufacture of a pharmaceutical preparation.
 12. The use according to claim 11, wherein the pharmaceutical preparation is used as an antiosteoporosis agent.
 13. The use according to claim 11, wherein the pharmaceutical preparation is used as a hypoglycemic agent.
 14. The use according to claim 11, wherein the pharmaceutical preparation is used in the treatment of tumor.
 15. The use according to claim 11, wherein the pharmaceutical preparation is used in animal for inhibiting the oxidation of low density lipoprotein.
 16. The use according to claim 11, wherein the pharmaceutical preparation is used in improving memory and learning.
 17. A use of the extract of Anoectochilus spp. according to claim 8 for the manufacture of a pharmaceutical preparation for hepatoprotection. 